Bonsai Garden at Lake Merritt

Q. I don’t understand all of the bonsai terms. Where can I find definitions?
A. There is a very good glossary on bonsaitalk.

Q. Are bonsai trees special clones, naturally miniature?
A. No. These trees would grow to full, natural height if planted in the ground.

Q. How do you keep them small?
A. The trees are kept small in two ways:

by limiting the amount of photosynthesis, accomplished by keeping the leaf mass to a minimum, by pinching, halving the leaves, or complete defoliation in summer (deciduous trees only). We pluck/cut needles of conifers to reduce foliage.

by limiting the amount of nutrients available to the plant. This is accomplished by root pruning every 1 – 3 years and not by limiting fertilizer.

Q. Are the trees starved to keep them small?
A. No, although that was done formerly by some. Most bonsai growers give their plants lots of fertilizer, organic or synthetic, and maintain appropriate size by pruning, pinching and root pruning. This system encourages growth and enables one to achieve a desired result sooner than if one were to limit nutrients.

Q. Do bonsai grow in regular potting soil?
A. No, they are grown in a soil that drains water very fast. Formulas differ among bonsai artists but the Bonsai Garden at Lake Merritt (BGLM) uses a Japanese soil called akadama with added materials such as expanded granite, charcoal, etc. to accomplish fast drainage. Akadama is available from various bonsai retailers.

Q. What is the wire for?
A. The annealed copper wire is placed on branches so that they can be arranged in pleasing ways. Wiring is kept on until the growth swells the branch. It is removed in order to prevent scarring of the bark. Branches will be wired this way regularly until the branch is old enough to maintain the styling and not return to its original configuration.

Q. I want to do bonsai but don’t have a yard. Can I keep it indoors?
A. No, with few exceptions. Almost all bonsai, except for tropicals, which are not traditional bonsai, are maintained outdoors at all times. The Japanese evolved the art with trees that worked in their climate, which is temperate: very hot and muggy in summer, cold in winter. Those who grow temperature-sensitive plants in cold winter areas, must protect them in various ways.

We are fortunate to have a wonderful gardening climate in the San Francisco Bay Area and can grow most bonsai readily. Our only lack is winter cold, although those far enough away from the Bay find that some plants benefit from their winter chill.

On the other hand, many who live in the summer high temperature parts of the Bay Area, may have to protect their plants with shade cloth.

Q. Are bonsai high maintenance?
A. It depends: on what you mean by that, how many plants you have, and how many qualified and reliable friends you have to care for them in your absence. There are four major areas of care: watering, fertilizing, pruning/pinching, and repotting/root pruning.

Watering – Bonsai require daily watering, with some exceptions, and twice daily watering in the summer if the sun is shining. Those who live in fog belts may water only once daily; those past the east Bay hills, for instance, may water three times daily. This immediately brings automated watering systems to mind. However, automated systems must be checked regularly and not depended upon completely. This is where those qualified and reliable friends come in. If you begin doing bonsai and join local clubs, chances are that you will make friends with people with whom you can arrange reciprocal watering schedules.

Fertilizing – the BGLM uses an organic fertilizer and applies it monthly. Some special plant conditions will require different fertilizing regimes, but they are typically done every 1 – 2 weeks. Others in the Bonsai community use slow release fertilizers, soluble fertilizers or traditional Japanese fertilizer cakes.

Pruning/pinching – Deciduous trees require pinching during the growth season to keep their compact appearance. They can typically go without pinching for a few weeks, even more. Conifer needles are removed and decandling done only in certain times of the year and generally there is a month-long window of opportunity.

Repotting/Root Pruning – this is done every 1 – 3 years, depending upon the density of the root growth of the plant. It is done only during the dormant season, which is short in San Francisco: November to February for most of us.

As you can see, it’s the watering that is high maintenance. If you think you can manage what has been described, consider joining a bonsai club and getting started.

Q. How can I get started in bonsai?
A. We conduct monthly demonstrations of bonsai creation and maintenance at the BGLM. They are held most months on the fourth Sunday of the month, from 1 to 3 pm. Check listings here and in local newspapers. We also recommend attending a meeting of one of the many California bonsai clubs, joining and going to workshops held by the clubs.

Q. There is rebar or bamboo on some of the trees. What is that for?
A. It’s there to bend the larger, woody branches. This is done on conifers and, as you saw from the Daimyo Oak, on some deciduous trees. Beginners and not a few experienced bonsai practitioners, find it amazing that trees withstand this treatment.

Q. In the tree gallery, there is a bonsai, #123, with no leaves on it during summer. What has happened to that tree?
A. The tree was defoliated, all leaves removed, in order to promote new smaller leaves and branching, or ramification, at the place where the leaves have been removed.